Labour, the Green party and the Liberal Democrats have called for the government to act on claims of widespread dishonesty by the medical professionals paid to compile benefits assessment reports, following a two-month investigation by Disability News Service (DNS).

The three parties spoke out after DNS shared the findings of the investigation with key opposition figures.

DNS has examined more than 20 cases in which claimants of personal independence payment (PIP) – which is replacing working-age disability living allowance – have described how the healthcare professionals who carried out their face-to-face assessments subsequently produced dishonest reports.

The dishonesty includes assessors refusing to accept further written evidence from medical experts; wrongly claiming that detailed physical examinations had been carried out during the assessment; refusing to list all of a claimant’s medications; ignoring or misreporting key evidence told to them in the assessment; and reporting that a claimant had refused to co-operate with a physical examination, when they were instead unable to complete it because of their impairment.

Jonathan Bartley (pictured), co-leader of the Green party, called for an independent investigation.

He said: “This investigation reveals that is not sick and disabled people who are lying but those who are assessing them.

“The shocking prevalence of inaccurate assessments which are denying desperately needed support obliterates any remaining pretence that PIP assessments are fair.

“The system should be looking after those who need help and acting with their best interests at heart, not working against them and making things worse.

“Behind each of these stories and the hundreds of complaints are people who are suffering, whose lives have been disrupted, turned upside down or in some cases destroyed.

“It is clear these cases are not isolated incidents. There should be a full-scale investigation as a matter of urgency to reveal the full extent of what is going on, and that should ideally be carried out independently of the DWP, to avoid any cover-up, as we saw over the deaths of benefit claimants.”

Debbie Abrahams, Labour’s shadow work and pensions secretary, said the evidence produced by DNS was “truly shocking”, and she repeated last year’s call by Labour to investigate the conduct of assessors.

“Last year, Labour called for the department to undertake an investigation into the conduct of assessors, yet ministers refused to take action.

“Unlike the work capability assessment, the government plans to continue assessing all disabled people for PIP, regardless of their condition and the fact that 65 per cent of PIP appeals are successful.

“The impact on disabled people of having to fight the DWP for support to which they are entitled cannot be underestimated; causing distress, anxiety and negatively impacting on their health.

“It is clear that the assessment process is wholly inappropriate and, in light of this investigation, ministers must take action now.”

The disabled Liberal Democrat peer Baroness [Celia] Thomas, who speaks for her party on disability, said the investigation and its findings were “timely” and called for DWP to audit all of its assessors.

She said the claims reflected the letters and emails she and other disabled peers receive about PIP assessors “who do not take proper notice of medical reports, do not listen properly to claimants and do not remember to ask about the reliability criteria which governs all descriptors”.

She said: “DWP needs to conduct a thorough audit of all assessors to make sure disabled people are not being penalised by assessors who are not up to the job.”

DWP has been handed eight cases of named claimants who have come forward to make allegations that healthcare professionals working for the outsourcing giants Capita and Atos lied in the reports they wrote after carrying out face-to-face assessments.

But DWP also turned down the opportunity to see many more cases, in which claimants have asked DNS not to reveal their personal details to the department.

Despite the findings of the investigation, DWP has refused to accept that there is any dishonesty at all among the medical professionals paid to compile assessment reports, and has refused to take any action to address the concerns.

Asked why there were so many cases of dishonesty involving assessors working for Capita and Atos, a DWP spokeswoman said: “We do not accept this is the case.”

She added: “We expect the highest standards from the contractors who carry out PIP assessments.

“We do not accept it to be the case that there is dishonesty amongst them.”

Asked whether DWP would act on the information provided by DNS, she said: “We are committed to making sure the PIP assessment process works fairly and effectively, which is why we welcome independent reviews such as the ones led by Paul Gray, the second of which is expected in April 2017.”

She added: “Assessment providers have their own complaints processes in place, and if claimants are not satisfied with providers’ response they will be signposted to the Independent Case Examiner (ICE).

“Over 1.9 million PIP claims have been decided since April 2013 to September 2016 and in this time only a tiny fraction of complaints regarding providers’ service standards have been upheld by ICE.

“If ICE upholds a complaint against the provider, the provider incurs a penalty charge and is also required to pay the claimant any financial redress recommended by ICE.

“PIP customer satisfaction is up by more than 10 per cent since last year, and we expect these trends to continue following new improvements.

“We continue to work with disability stakeholders to ensure the PIP assessment process is working well.”

Asked if there was a serious problem with Atos and Capita assessors lying in their assessment reports, she said: “No, our providers are committed to providing a high-quality, sensitive and respectful service by conducting fair, accurate and objective assessments.

“Independent audit is in place to ensure advice provided to DWP decision makers is of suitable quality, fully explained and justified.

“Both Atos and Capita are required to ensure that the health professionals carrying out assessments have knowledge of the clinical aspects and likely functional effects of a wide range of health conditions and impairments.

“All health professionals undertaking assessments on behalf of DWP must be registered practitioners who have also met requirements around training and competence.

“They must be: an occupational therapist, level one nurse, physiotherapist, paramedic or doctor.

“They must also be fully registered and have at least two years post full-registration experience.”

She added: “All health professionals receive comprehensive training in disability analysis which includes a functional evaluation as to how medical conditions and the long-term medical treatment of those conditions affect an individual’s ability to perform day-to-day activities.

“Prior to carrying out an assessment, the health professional routinely refreshes their knowledge of any condition with which they are not fully familiar.”

She added: “We expect the highest standards from the contractors who carry out PIP assessments, and work closely with them to ensure PIP is working in the best way possible.

“We work extensively with the PIP assessment providers (Atos and Capita) and disability representative groups to make improvements to guidance, training and audit procedures in order to ensure a quality service.”

Capita refused to answer any questions about the allegations, including how many complaints it had received during 2016 about assessors not being truthful in their assessment reports; whether it believed this was a serious problem; and why it believed there were so many cases in which assessors were apparently failing to complete their assessment reports honestly.

Instead, it delivered the following statement: “We expect all of our assessors to undertake assessments as outlined by DWP and in-line with our comprehensive training.

“We expect all assessors to behave in a way that meets both our high professional standards and those of their professions.

“We are not involved in the decision making process or informed of claimants’ outcomes.”

Atos acknowledged receipt of an email from DNS detailing the investigation, but refused to respond further.